Electroporation of biological membranes from multicellular to nano scales

Electroporation, widely used in research and applications, is briefly reviewed. Both cell and artificial planar bilayer membranes exhibit dramatic changes if the transmembrane voltage is raised to ~0.2 to 1 V by various electric field pulses. Ionic and molecular transport increases by orders of magnitude, with both reversible and irreversible outcomes. Initially the term breakdown was used, but ion pair generation of classic dielectric breakdown was ruled out. Instead, a stochastic pore hypothesis is consistent with features of electroporation in planar lipid membranes. There is a rapid, nonlinear conduction increase through a rapidly evolving pore population, and this causes the fast membrane discharge previously termed "breakdown". Phenomena due to primary aqueous pores and secondary processes such as heating and chemical exchange have been observed in planar bilayers, cell single systems encountered mainly in vitro, multicellular systems relevant to in vivo applications, and possibly subcellular structures such as mitochondria. For membrane systems that approach nanoscales, modified behavior should occur because of conformational constraints, and deterministic processes may become more important. Understanding electroporation is a subset of a general problem: obtaining a quantitative description of how electromagnetic field-altered changes in chemical species within a biological system govern observed effects.